The invention relates generally to telecommunications connectors and in particular to a telecommunications plug and outlet having enhanced performance characteristics. Improvements in telecommunications systems have resulted in the ability to transmit voice and/or data signals along transmission lines at increasingly higher frequencies. Several industry standards that specify multiple performance levels of twisted-pair cabling components have been established. The primary references, considered by many to be the international benchmarks for commercially based telecommunications components and installations, are standards ANSI/TIA/EIA-568-A (/568) Commercial Building Telecommunications Cabling Standard and 150/IEC 11801 (/11801), generic cabling for customer premises. For example, Category 3, 4 and 5 cable and connecting hardware are specified in both /568 and /11801, as well as other national and regional specifications. In these specifications, transmission requirements for Category 3 components are specified up to 16 MHZ. Transmission requirements for Category 4 components are specified up to 20 MHZ. Transmission requirements for Category 5 components are specified up to 100 MHZ. New standards are being developed continuously and currently it is expected that future standards will require transmission requirements of at least 600 MHZ. To achieve such transmission rates, fully shielded twisted pair cable will be necessary in which each pair is individually wrapped in a foil or screen. In addition, all pairs are wrapped together in a layer of foil or screen.
The above referenced transmission requirements also specify limits on near-end crosstalk (NEXT). Telecommunications connectors are organized in sets of pairs, typically made up of a tip and ring connector. As telecommunications connectors are reduced in size, adjacent pairs are placed closer to each other creating crosstalk between adjacent pairs. To comply with the near-end crosstalk requirements, a variety of techniques are used in the art.
U.S. Pat. No. 5,593,311 discloses a shielded compact data connector designed to reduce crosstalk between contacts of the connector. Pairs of contacts are placed within metallic channels. When the connectors are mated, the channels abut against each other to enclose each pair in a metallic shield. One disadvantage to the design in U.S. Pat. No. 5,593,311 is that the metallic channels are joined at a butt joint; one surface abuts against the adjacent surface with no overlap. Since all components include some manufacturing tolerance, there is a potential for gaps between the shields thereby reducing the shielding effect. Another disadvantage is that wires having the foil removed can be exposed to each other at the rear of the connector thus leading to crosstalk. Thus, there is a perceived need in the art for a connector having improved pair shielding.
The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the enhanced performance telecommunications connector of the present invention. In one embodiment, the connector is made up of a plug and outlet which, when mated, define four shielded quadrants, each of which houses a pair of contacts. In another embodiment, the connector is made up of a plug and outlet which, when mated, define two shielded quadrants, each of which houses a pair of contacts. In a further embodiment of the present invention, a printed circuit board (PCB) connector is provided wherein the connector is made up of a plug and outlet which, when mated, define four shielded quadrants, each of which houses a pair of contacts. In this embodiment, the connector is particularly suitable for mounting onto a circuit board. In yet another embodiment of the present invention, an improved plug top cover is provided having a metallic latch subassembly which allows for a more direct electrical path from a plug cable screen to an outlet cable screen. In all of the embodiments described herein which set forth the improved connector of the present invention, the shield members within the plug overlap and shield members within the outlet overlap. In addition, shield members within the outlet overlap adjacent shield members on the plug when mated. Overlapping the shield members at each shield member juncture provides enhanced shielding and reduced crosstalk.
The above-discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings.